1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate * CDDL HEADER START
3*0Sstevel@tonic-gate *
4*0Sstevel@tonic-gate * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate * (the "License"). You may not use this file except in compliance
7*0Sstevel@tonic-gate * with the License.
8*0Sstevel@tonic-gate *
9*0Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate * and limitations under the License.
13*0Sstevel@tonic-gate *
14*0Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate *
20*0Sstevel@tonic-gate * CDDL HEADER END
21*0Sstevel@tonic-gate */
22*0Sstevel@tonic-gate /*
23*0Sstevel@tonic-gate * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
24*0Sstevel@tonic-gate * Use is subject to license terms.
25*0Sstevel@tonic-gate */
26*0Sstevel@tonic-gate
27*0Sstevel@tonic-gate #pragma ident "%Z%%M% %I% %E% SMI"
28*0Sstevel@tonic-gate
29*0Sstevel@tonic-gate #include <sys/systm.h>
30*0Sstevel@tonic-gate #include <sys/types.h>
31*0Sstevel@tonic-gate #include <sys/vnode.h>
32*0Sstevel@tonic-gate #include <sys/file.h>
33*0Sstevel@tonic-gate #include <sys/buf.h>
34*0Sstevel@tonic-gate #include <sys/ddi.h>
35*0Sstevel@tonic-gate #include <sys/errno.h>
36*0Sstevel@tonic-gate #include <sys/cmn_err.h>
37*0Sstevel@tonic-gate #include <sys/fs/ufs_inode.h>
38*0Sstevel@tonic-gate #include <sys/fs/ufs_filio.h>
39*0Sstevel@tonic-gate #include <sys/fs/ufs_snap.h>
40*0Sstevel@tonic-gate #include <sys/fssnap_if.h>
41*0Sstevel@tonic-gate #include <sys/sysmacros.h>
42*0Sstevel@tonic-gate #include <sys/modctl.h>
43*0Sstevel@tonic-gate #include <sys/fs/ufs_bio.h>
44*0Sstevel@tonic-gate #include <sys/debug.h>
45*0Sstevel@tonic-gate #include <sys/kmem.h>
46*0Sstevel@tonic-gate #include <sys/inttypes.h>
47*0Sstevel@tonic-gate #include <sys/vfs.h>
48*0Sstevel@tonic-gate #include <sys/disp.h>
49*0Sstevel@tonic-gate #include <sys/atomic.h>
50*0Sstevel@tonic-gate #include <sys/conf.h>
51*0Sstevel@tonic-gate #include <sys/param.h>
52*0Sstevel@tonic-gate #include <sys/policy.h>
53*0Sstevel@tonic-gate
54*0Sstevel@tonic-gate static int ufs_snap_init_backfile(int *, int, vnode_t ***, struct ufsvfs *);
55*0Sstevel@tonic-gate static void release_backing_vnodes(vnode_t ***, int);
56*0Sstevel@tonic-gate static int ufs_snap_find_candidates(void *, struct ufsvfs *, int);
57*0Sstevel@tonic-gate
58*0Sstevel@tonic-gate /*
59*0Sstevel@tonic-gate * Create a snapshot on a file system
60*0Sstevel@tonic-gate */
61*0Sstevel@tonic-gate int
ufs_snap_create(struct vnode * vp,struct fiosnapcreate_multi * fiosnapp,cred_t * cr)62*0Sstevel@tonic-gate ufs_snap_create(struct vnode *vp, struct fiosnapcreate_multi *fiosnapp,
63*0Sstevel@tonic-gate cred_t *cr)
64*0Sstevel@tonic-gate {
65*0Sstevel@tonic-gate int error = 0;
66*0Sstevel@tonic-gate struct ufsvfs *ufsvfsp = VTOI(vp)->i_ufsvfs;
67*0Sstevel@tonic-gate struct fs *fs = ufsvfsp->vfs_fs;
68*0Sstevel@tonic-gate vnode_t **bfvpp = NULL;
69*0Sstevel@tonic-gate struct lockfs lf;
70*0Sstevel@tonic-gate void *snapid = NULL;
71*0Sstevel@tonic-gate
72*0Sstevel@tonic-gate u_offset_t nchunks;
73*0Sstevel@tonic-gate uint_t chunksize, fragsperchunk;
74*0Sstevel@tonic-gate
75*0Sstevel@tonic-gate /*
76*0Sstevel@tonic-gate * Only privilege processes can create a snapshot for now. This
77*0Sstevel@tonic-gate * would be better if it was based on the permissions of the device
78*0Sstevel@tonic-gate * file.
79*0Sstevel@tonic-gate */
80*0Sstevel@tonic-gate if (secpolicy_fs_config(cr, ufsvfsp->vfs_vfs) != 0)
81*0Sstevel@tonic-gate return (EPERM);
82*0Sstevel@tonic-gate
83*0Sstevel@tonic-gate /*
84*0Sstevel@tonic-gate * There is no reason to make a snapshot of a read-only file system
85*0Sstevel@tonic-gate */
86*0Sstevel@tonic-gate if (fs->fs_ronly) {
87*0Sstevel@tonic-gate fiosnapp->error = FIOCOW_EREADONLY;
88*0Sstevel@tonic-gate return (EROFS);
89*0Sstevel@tonic-gate }
90*0Sstevel@tonic-gate
91*0Sstevel@tonic-gate /*
92*0Sstevel@tonic-gate * Initialize the backing files to store old data. This assumes any
93*0Sstevel@tonic-gate * preallocation and setup has been done already.
94*0Sstevel@tonic-gate * ufs_snap_init_backfile() allocates and returns a pointer to
95*0Sstevel@tonic-gate * a null-terminated array of vnodes in bfvpp.
96*0Sstevel@tonic-gate */
97*0Sstevel@tonic-gate error = ufs_snap_init_backfile(fiosnapp->backfiledesc,
98*0Sstevel@tonic-gate fiosnapp->backfilecount, &bfvpp, ufsvfsp);
99*0Sstevel@tonic-gate if (error) {
100*0Sstevel@tonic-gate fiosnapp->error = FIOCOW_EBACKFILE;
101*0Sstevel@tonic-gate return (error);
102*0Sstevel@tonic-gate }
103*0Sstevel@tonic-gate
104*0Sstevel@tonic-gate /*
105*0Sstevel@tonic-gate * File system must be write locked to prevent updates while
106*0Sstevel@tonic-gate * the snapshot is being established.
107*0Sstevel@tonic-gate */
108*0Sstevel@tonic-gate if ((error = ufs_fiolfss(vp, &lf)) != 0) {
109*0Sstevel@tonic-gate release_backing_vnodes(&bfvpp, fiosnapp->backfilecount);
110*0Sstevel@tonic-gate return (error);
111*0Sstevel@tonic-gate }
112*0Sstevel@tonic-gate
113*0Sstevel@tonic-gate if (!LOCKFS_IS_ULOCK(&lf)) {
114*0Sstevel@tonic-gate release_backing_vnodes(&bfvpp, fiosnapp->backfilecount);
115*0Sstevel@tonic-gate fiosnapp->error = FIOCOW_EULOCK;
116*0Sstevel@tonic-gate return (EINVAL);
117*0Sstevel@tonic-gate }
118*0Sstevel@tonic-gate
119*0Sstevel@tonic-gate lf.lf_lock = LOCKFS_WLOCK;
120*0Sstevel@tonic-gate lf.lf_flags = 0;
121*0Sstevel@tonic-gate lf.lf_comment = NULL;
122*0Sstevel@tonic-gate if ((error = ufs_fiolfs(vp, &lf, 1)) != 0) {
123*0Sstevel@tonic-gate release_backing_vnodes(&bfvpp, fiosnapp->backfilecount);
124*0Sstevel@tonic-gate fiosnapp->error = FIOCOW_EWLOCK;
125*0Sstevel@tonic-gate return (EINVAL);
126*0Sstevel@tonic-gate }
127*0Sstevel@tonic-gate
128*0Sstevel@tonic-gate /*
129*0Sstevel@tonic-gate * File system must be fairly consistent to enable snapshots
130*0Sstevel@tonic-gate */
131*0Sstevel@tonic-gate if (fs->fs_clean != FSACTIVE &&
132*0Sstevel@tonic-gate fs->fs_clean != FSSTABLE &&
133*0Sstevel@tonic-gate fs->fs_clean != FSCLEAN &&
134*0Sstevel@tonic-gate fs->fs_clean != FSLOG) {
135*0Sstevel@tonic-gate fiosnapp->error = FIOCOW_ECLEAN;
136*0Sstevel@tonic-gate error = EINVAL;
137*0Sstevel@tonic-gate goto unlockout;
138*0Sstevel@tonic-gate }
139*0Sstevel@tonic-gate
140*0Sstevel@tonic-gate /*
141*0Sstevel@tonic-gate * Only one snapshot is allowed per file system, so error if
142*0Sstevel@tonic-gate * a snapshot is already enabled.
143*0Sstevel@tonic-gate */
144*0Sstevel@tonic-gate if (ufsvfsp->vfs_snapshot) {
145*0Sstevel@tonic-gate fiosnapp->error = FIOCOW_EBUSY;
146*0Sstevel@tonic-gate error = EBUSY;
147*0Sstevel@tonic-gate goto unlockout;
148*0Sstevel@tonic-gate }
149*0Sstevel@tonic-gate
150*0Sstevel@tonic-gate /* Tell bio.c how to call our strategy routine. XXX ugly hack */
151*0Sstevel@tonic-gate if (bio_snapshot_strategy == NULL)
152*0Sstevel@tonic-gate bio_snapshot_strategy =
153*0Sstevel@tonic-gate (void (*) (void *, buf_t *))fssnap_strategy;
154*0Sstevel@tonic-gate
155*0Sstevel@tonic-gate /*
156*0Sstevel@tonic-gate * use chunk size that is passed in, or the file system
157*0Sstevel@tonic-gate * block size if it is zero. For most cases, the file system
158*0Sstevel@tonic-gate * block size will be reasonably efficient. A larger
159*0Sstevel@tonic-gate * chunksize uses less memory but may potentially induce more
160*0Sstevel@tonic-gate * I/O copying the larger chunks aside.
161*0Sstevel@tonic-gate */
162*0Sstevel@tonic-gate if (fiosnapp->chunksize != 0)
163*0Sstevel@tonic-gate chunksize = fiosnapp->chunksize;
164*0Sstevel@tonic-gate else
165*0Sstevel@tonic-gate chunksize = fs->fs_bsize * 4;
166*0Sstevel@tonic-gate
167*0Sstevel@tonic-gate
168*0Sstevel@tonic-gate /*
169*0Sstevel@tonic-gate * compute the number of chunks in this whole file system. Since
170*0Sstevel@tonic-gate * the UFS allocation bitmaps are in units of fragments, we first
171*0Sstevel@tonic-gate * compute the number of fragments per chunk. Things work out
172*0Sstevel@tonic-gate * nicer if the chunk size is a power-of-two multiple of the
173*0Sstevel@tonic-gate * fragment size.
174*0Sstevel@tonic-gate */
175*0Sstevel@tonic-gate if ((chunksize < fs->fs_fsize) || (chunksize % fs->fs_fsize != 0)) {
176*0Sstevel@tonic-gate fiosnapp->error = FIOCOW_ECHUNKSZ;
177*0Sstevel@tonic-gate error = EINVAL;
178*0Sstevel@tonic-gate goto unlockout;
179*0Sstevel@tonic-gate }
180*0Sstevel@tonic-gate fragsperchunk = chunksize >> fs->fs_fshift;
181*0Sstevel@tonic-gate nchunks = (fs->fs_size + fragsperchunk) / fragsperchunk;
182*0Sstevel@tonic-gate
183*0Sstevel@tonic-gate /*
184*0Sstevel@tonic-gate * Create and initialize snapshot state and allocate/initialize
185*0Sstevel@tonic-gate * translation table. This does the real work of taking the snapshot.
186*0Sstevel@tonic-gate */
187*0Sstevel@tonic-gate snapid = fssnap_create(nchunks, chunksize, fiosnapp->maxsize, vp,
188*0Sstevel@tonic-gate fiosnapp->backfilecount, bfvpp, fiosnapp->backfilename,
189*0Sstevel@tonic-gate fiosnapp->backfilesize);
190*0Sstevel@tonic-gate if (snapid == NULL) {
191*0Sstevel@tonic-gate fiosnapp->error = FIOCOW_ECREATE;
192*0Sstevel@tonic-gate error = EINVAL;
193*0Sstevel@tonic-gate goto unlockout;
194*0Sstevel@tonic-gate }
195*0Sstevel@tonic-gate
196*0Sstevel@tonic-gate error = ufs_snap_find_candidates(snapid, ufsvfsp, chunksize);
197*0Sstevel@tonic-gate fiosnapp->snapshotnumber = fssnap_create_done(snapid);
198*0Sstevel@tonic-gate
199*0Sstevel@tonic-gate if (error) {
200*0Sstevel@tonic-gate cmn_err(CE_WARN, "ufs_snap_create: failed scanning bitmaps, "
201*0Sstevel@tonic-gate "error = %d.", error);
202*0Sstevel@tonic-gate fiosnapp->error = FIOCOW_EBITMAP;
203*0Sstevel@tonic-gate goto unlockout;
204*0Sstevel@tonic-gate }
205*0Sstevel@tonic-gate
206*0Sstevel@tonic-gate ufsvfsp->vfs_snapshot = snapid;
207*0Sstevel@tonic-gate
208*0Sstevel@tonic-gate unlockout:
209*0Sstevel@tonic-gate /*
210*0Sstevel@tonic-gate * Unlock the file system
211*0Sstevel@tonic-gate */
212*0Sstevel@tonic-gate lf.lf_lock = LOCKFS_ULOCK;
213*0Sstevel@tonic-gate lf.lf_flags = 0;
214*0Sstevel@tonic-gate if ((ufs_fiolfs(vp, &lf, 1) != 0) && !error) {
215*0Sstevel@tonic-gate fiosnapp->error = FIOCOW_ENOULOCK;
216*0Sstevel@tonic-gate error = EINVAL;
217*0Sstevel@tonic-gate } else {
218*0Sstevel@tonic-gate fiosnapp->error = 0;
219*0Sstevel@tonic-gate }
220*0Sstevel@tonic-gate
221*0Sstevel@tonic-gate /* clean up the snapshot if an error occurred. */
222*0Sstevel@tonic-gate if (error && snapid != NULL)
223*0Sstevel@tonic-gate (void) fssnap_delete(&snapid);
224*0Sstevel@tonic-gate else if (error && bfvpp != NULL)
225*0Sstevel@tonic-gate release_backing_vnodes(&bfvpp, fiosnapp->backfilecount);
226*0Sstevel@tonic-gate
227*0Sstevel@tonic-gate return (error);
228*0Sstevel@tonic-gate }
229*0Sstevel@tonic-gate
230*0Sstevel@tonic-gate static int
ufs_snap_init_backfile(int * filedesc,int count,vnode_t *** vppp,struct ufsvfs * ufsvfsp)231*0Sstevel@tonic-gate ufs_snap_init_backfile(int *filedesc, int count, vnode_t ***vppp,
232*0Sstevel@tonic-gate struct ufsvfs *ufsvfsp)
233*0Sstevel@tonic-gate {
234*0Sstevel@tonic-gate file_t *fp;
235*0Sstevel@tonic-gate vnode_t **vpp;
236*0Sstevel@tonic-gate int i;
237*0Sstevel@tonic-gate
238*0Sstevel@tonic-gate vpp = (vnode_t **)kmem_zalloc((count + 1) * sizeof (vnode_t *),
239*0Sstevel@tonic-gate KM_SLEEP);
240*0Sstevel@tonic-gate *vppp = vpp;
241*0Sstevel@tonic-gate for (i = 0; i < count; i++) {
242*0Sstevel@tonic-gate if ((fp = getf(*filedesc)) == NULL) {
243*0Sstevel@tonic-gate release_backing_vnodes(vppp, count);
244*0Sstevel@tonic-gate *vppp = NULL;
245*0Sstevel@tonic-gate return (EBADF);
246*0Sstevel@tonic-gate }
247*0Sstevel@tonic-gate
248*0Sstevel@tonic-gate ASSERT(fp->f_vnode != NULL);
249*0Sstevel@tonic-gate VN_HOLD(fp->f_vnode);
250*0Sstevel@tonic-gate
251*0Sstevel@tonic-gate *vpp = fp->f_vnode;
252*0Sstevel@tonic-gate releasef(*filedesc);
253*0Sstevel@tonic-gate filedesc++;
254*0Sstevel@tonic-gate
255*0Sstevel@tonic-gate /* make sure the backing file is on a different file system */
256*0Sstevel@tonic-gate if ((*vpp)->v_vfsp == ufsvfsp->vfs_vfs) {
257*0Sstevel@tonic-gate release_backing_vnodes(vppp, count);
258*0Sstevel@tonic-gate *vppp = NULL;
259*0Sstevel@tonic-gate return (EINVAL);
260*0Sstevel@tonic-gate }
261*0Sstevel@tonic-gate vpp++;
262*0Sstevel@tonic-gate }
263*0Sstevel@tonic-gate return (0);
264*0Sstevel@tonic-gate }
265*0Sstevel@tonic-gate
266*0Sstevel@tonic-gate static void
release_backing_vnodes(vnode_t *** bvppp,int count)267*0Sstevel@tonic-gate release_backing_vnodes(vnode_t ***bvppp, int count)
268*0Sstevel@tonic-gate {
269*0Sstevel@tonic-gate vnode_t **vpp;
270*0Sstevel@tonic-gate
271*0Sstevel@tonic-gate vpp = *bvppp;
272*0Sstevel@tonic-gate while (*vpp) {
273*0Sstevel@tonic-gate VN_RELE(*vpp);
274*0Sstevel@tonic-gate *vpp++ = NULL;
275*0Sstevel@tonic-gate }
276*0Sstevel@tonic-gate kmem_free(*bvppp, (count + 1) * sizeof (vnode_t *));
277*0Sstevel@tonic-gate *bvppp = NULL;
278*0Sstevel@tonic-gate }
279*0Sstevel@tonic-gate
280*0Sstevel@tonic-gate static int
ufs_snap_find_candidates(void * snapid,struct ufsvfs * ufsvfsp,int chunksize)281*0Sstevel@tonic-gate ufs_snap_find_candidates(void *snapid, struct ufsvfs *ufsvfsp, int chunksize)
282*0Sstevel@tonic-gate {
283*0Sstevel@tonic-gate struct fs *fs = ufsvfsp->vfs_fs;
284*0Sstevel@tonic-gate struct buf *cgbp; /* cylinder group buffer */
285*0Sstevel@tonic-gate struct cg *cgp; /* cylinder group data */
286*0Sstevel@tonic-gate ulong_t cg;
287*0Sstevel@tonic-gate ulong_t cgbase;
288*0Sstevel@tonic-gate ulong_t chunk;
289*0Sstevel@tonic-gate uchar_t *blksfree;
290*0Sstevel@tonic-gate
291*0Sstevel@tonic-gate ulong_t curfrag;
292*0Sstevel@tonic-gate int error = 0;
293*0Sstevel@tonic-gate
294*0Sstevel@tonic-gate /*
295*0Sstevel@tonic-gate * read through each ufs cylinder group and fetch the fragment
296*0Sstevel@tonic-gate * allocation bitmap. UFS indicates a fragment is allocated by
297*0Sstevel@tonic-gate * a zero bit (not a one bit) in the fragment offset.
298*0Sstevel@tonic-gate */
299*0Sstevel@tonic-gate cgbase = 0LL;
300*0Sstevel@tonic-gate for (cg = 0; cg < fs->fs_ncg; cg++) {
301*0Sstevel@tonic-gate /* read the cylinder group in */
302*0Sstevel@tonic-gate cgbp = BREAD(ufsvfsp->vfs_dev,
303*0Sstevel@tonic-gate (daddr_t)fsbtodb(fs, cgtod(fs, cg)), (int)fs->fs_cgsize);
304*0Sstevel@tonic-gate if ((error = geterror(cgbp)) != 0) {
305*0Sstevel@tonic-gate brelse(cgbp);
306*0Sstevel@tonic-gate goto errout;
307*0Sstevel@tonic-gate }
308*0Sstevel@tonic-gate cgp = cgbp->b_un.b_cg;
309*0Sstevel@tonic-gate
310*0Sstevel@tonic-gate /* check the magic number */
311*0Sstevel@tonic-gate if (cgp->cg_magic != CG_MAGIC) {
312*0Sstevel@tonic-gate cmn_err(CE_WARN, "ufs_snap_find_candidates: cg %lu "
313*0Sstevel@tonic-gate "magic number (0x%x) does not match expected "
314*0Sstevel@tonic-gate "magic number (0x%x)", cg, cgp->cg_magic, CG_MAGIC);
315*0Sstevel@tonic-gate error = EIO;
316*0Sstevel@tonic-gate goto errout;
317*0Sstevel@tonic-gate }
318*0Sstevel@tonic-gate
319*0Sstevel@tonic-gate blksfree = cg_blksfree(cgp);
320*0Sstevel@tonic-gate
321*0Sstevel@tonic-gate /*
322*0Sstevel@tonic-gate * go through the allocation bitmap and set the
323*0Sstevel@tonic-gate * corresponding bit in the candidate map.
324*0Sstevel@tonic-gate */
325*0Sstevel@tonic-gate for (curfrag = 0; curfrag < cgp->cg_ndblk; curfrag++) {
326*0Sstevel@tonic-gate if (isclr(blksfree, curfrag)) {
327*0Sstevel@tonic-gate /*
328*0Sstevel@tonic-gate * this assumes chunksize is a multiple of
329*0Sstevel@tonic-gate * the fragment size
330*0Sstevel@tonic-gate */
331*0Sstevel@tonic-gate chunk = (ulong_t)((cgbase + curfrag) /
332*0Sstevel@tonic-gate (chunksize >> fs->fs_fshift));
333*0Sstevel@tonic-gate
334*0Sstevel@tonic-gate fssnap_set_candidate(snapid, chunk);
335*0Sstevel@tonic-gate /*
336*0Sstevel@tonic-gate * no need to scan the rest of this chunk since
337*0Sstevel@tonic-gate * it is already marked, so skip to the next
338*0Sstevel@tonic-gate */
339*0Sstevel@tonic-gate curfrag += ((chunksize >> fs->fs_fshift) -
340*0Sstevel@tonic-gate ((cgbase + curfrag) %
341*0Sstevel@tonic-gate (chunksize >> fs->fs_fshift))) - 1;
342*0Sstevel@tonic-gate }
343*0Sstevel@tonic-gate }
344*0Sstevel@tonic-gate
345*0Sstevel@tonic-gate cgbase += cgp->cg_ndblk;
346*0Sstevel@tonic-gate ASSERT(cgbase <= fs->fs_size);
347*0Sstevel@tonic-gate brelse(cgbp);
348*0Sstevel@tonic-gate } /* cylinder group loop */
349*0Sstevel@tonic-gate
350*0Sstevel@tonic-gate ASSERT(cgbase == fs->fs_size);
351*0Sstevel@tonic-gate
352*0Sstevel@tonic-gate errout:
353*0Sstevel@tonic-gate return (error);
354*0Sstevel@tonic-gate }
355*0Sstevel@tonic-gate
356*0Sstevel@tonic-gate
357*0Sstevel@tonic-gate int
ufs_snap_delete(struct vnode * vp,struct fiosnapdelete * fiosnapp,cred_t * cr)358*0Sstevel@tonic-gate ufs_snap_delete(struct vnode *vp, struct fiosnapdelete *fiosnapp, cred_t *cr)
359*0Sstevel@tonic-gate {
360*0Sstevel@tonic-gate struct ufsvfs *ufsvfsp = VTOI(vp)->i_ufsvfs;
361*0Sstevel@tonic-gate struct fs *fs = ufsvfsp->vfs_fs;
362*0Sstevel@tonic-gate
363*0Sstevel@tonic-gate /*
364*0Sstevel@tonic-gate * Initialize fields in the user's buffer
365*0Sstevel@tonic-gate */
366*0Sstevel@tonic-gate fiosnapp->error = 0;
367*0Sstevel@tonic-gate
368*0Sstevel@tonic-gate /*
369*0Sstevel@tonic-gate * No snapshot exists, we're done.
370*0Sstevel@tonic-gate */
371*0Sstevel@tonic-gate if (ufsvfsp->vfs_snapshot == NULL)
372*0Sstevel@tonic-gate return (ENOENT);
373*0Sstevel@tonic-gate
374*0Sstevel@tonic-gate /*
375*0Sstevel@tonic-gate * must have sufficient privileges.
376*0Sstevel@tonic-gate */
377*0Sstevel@tonic-gate if (secpolicy_fs_config(cr, ufsvfsp->vfs_vfs) != 0)
378*0Sstevel@tonic-gate return (EPERM);
379*0Sstevel@tonic-gate
380*0Sstevel@tonic-gate /*
381*0Sstevel@tonic-gate * Readonly file system
382*0Sstevel@tonic-gate */
383*0Sstevel@tonic-gate if (fs->fs_ronly) {
384*0Sstevel@tonic-gate fiosnapp->error = FIOCOW_EREADONLY;
385*0Sstevel@tonic-gate return (EROFS);
386*0Sstevel@tonic-gate }
387*0Sstevel@tonic-gate
388*0Sstevel@tonic-gate /* free the data structures and clear the vfs_snapshot field. */
389*0Sstevel@tonic-gate fiosnapp->snapshotnumber = fssnap_delete(&ufsvfsp->vfs_snapshot);
390*0Sstevel@tonic-gate
391*0Sstevel@tonic-gate if (fiosnapp->snapshotnumber == -1)
392*0Sstevel@tonic-gate return (EINVAL);
393*0Sstevel@tonic-gate
394*0Sstevel@tonic-gate return (0);
395*0Sstevel@tonic-gate }
396